Method of treating coal



' Patented Nov. 11, 1930 UNITED STATES.

PATENT- OFFICE ERNEST VICTOR COLLINS, JR., OF BROOKLYN, NEW YORK, ASSIGNOR TO DELAWARE, LACKAWANNA & WESTERN COAL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY J METHOD OF TREATING COAL No Drawing.

This invention relates to the treatment of storage anthracite coal to remove therefrom the surface discoloration which takes place in storage and to restore essentially the original appearance of the fresh mined coal.

Fresh mined coal, that is coal which is mined and shipped for immediate-consumption, has a jet black color and a bright luster. Owing to the seasonal demand for coal, large quantities of fresh mined coal are placed in storage whenever possible in order to avert a shortage in the fall and Winter months. Such coal is known in the trade as storage coal.-

Coal so stored does not deteriorate as a fuel but the physical appearance is altered.

The coal becomes a dull grey in appearance and a considerable portion of it becomes badly discolored zby metallic compounds.

The consuming public, who are accustomed 2 to recognize anthracite coal by its jet black color and luster, often assume that coal which has been held in storage and has thus lost its characteristic appearance is poor in quality. The original fresh mined coal ap- 2 pearance cannot .be restored by ordinary washing. Consequently serious losses are sustained by the producer because this storage coal does not command the price of fresh mined coal, although analysis indicates that the change is only one of appearance and there is no loss of fuel value or consequential change in chemical composition.

The iron in the mineral matter of coal is considered to be almost wholly present in combination with sulphur. Under the infiuence of atmospheric exposure the iron sulphides become oxidized presumably to insoluble basic sulphates, oxides, and other compounds imparting to the coal a rusty appearance. Other reactions go on and other metallic compounds may show on the surface. The longer the coal is in storage and consequently the longer it is exposed to atmospheric influences, the greater usually becomes the discoloration.

It is the obj ectof .the present invention to provide a 'method of treating storage coal to' remove the surface discoloration and restore its original characteristic color and 59 bright luster. l

Application flled February 14, 1930. Serial No. 428,495.

I have discovered that the surface discoloration of storage coal can be removed and the original appearance of the coal restored by treating the coal under appropriate conditions with a solution of hydrochlooric acid containing a small amount of titanium trichloride (TiCl or Ti Cl As an example of the method, I prepare a 10% solution by volume of hydrochloric acid and add thereto 10% by volume of a 15% solution of titanium trichloride, thus providing approximately 1.5% of titanium trichloride in the hydrochloric acid solution. The discolored coal is immersed in this solution at normal atmospheric temperatures for a period suflicient to accomplish the object, usually a few minutes, after which the coal is removed from the solution and may be washed or sprayed with water. The solution may be heated to any desired temperature to accelerate the reaction. The strength of the solution may vary widely depending upon the degree of discoloration of the coal.

The action is more rapid and thorough if the coal is agitated in the solution, thereby producing a scrubbing action. A practical means of accomplishing this action is by use of a jig, Well known in the coal industry as an apparatus for separating coal from impurities, the principle of which is based on the difference in specific gravity of coal and rock or slate. Thls separation in the preparation of domestic sizes of anthracite is accomplished in a large tank filled with water. The action of a plunger about two feet below the surface floats the coal to the surface,

whence it can be removed. Instead of water,

the jig is filled with the hydrochloric acid- .titanium trichloride solution when it is desired to treat coal for the purpose of removing the discoloration. 5

The solution of hydrochloric acid and titanium trichlo'ride can be recovered and reused until it becomes too heavily contaminated with substances dissolved from the coal, the concentration of the solution being maintained by the periodic addition of small quantities of hydrochloric acid and/or titanium tri-chloride, if necessary.

- Various changes may be made in the -pro-" cedure employed herein without departing from the invention or sacrificing any of the advantages thereof. a

I claim:

The method of restoring the luster and improving the appearance of discolored coal which com rises treating it with a solution o fdhydroch ioric acid and titanium trichlor1 0.

In'testimony whereof I aflix my si nature.

ERNEST VICTOR COLLIN JR. 

